1. Prior Art
The prior art appears to be best exemplified by the following patents:
______________________________________ Banczak 4,021,252 May 3, 1977 Hwang 4,070,322 Jan. 24, 1978 Hertz 3,994,736 Nov. 30, 1976 Ostergren 3,846,141 Nov. 5, 1974 ______________________________________
2. Field of the Invention
This invention relates to ink jet printing compositions suitable for forming colored indicia on a variety of substrates including food products, for example citrus or any light colored fruit, eggs, hard candy, meat, animal hides; packaging materials in contact with food, for example egg cartons, or other paper and metal food packaging materials.
The invention of this application relates especially to ink jet printing compositions and their use in producing markings or other indicia on certain food products and food packaging. The compositions are particularly useful in ink jet printing on waxed or waxy surfaces such as citrus fruits.
Ink jet printing techniques, although of comparatively recent development in the art of applying decorative and/or identifying indicia to a substrate, are of increasing importance. In general, such techniques impose rigid requirements on the ink compositions. To be suitable for use as a jet ink, the compositions must meet rigid requirements of viscosity and resistivity, solubility, compatibility of components and wettability of substrate; the ink must be quick-drying and smear resistant without clogging the ink jet nozzle and must permit clean-up of the machine components with minimum effort. At the same time, such compositions must also be adapted for satisfactory performance in the particular end use for which they are specifically intended.
It has now been found that ink jet printing techniques may be applied and used to form markings or other identifying indicia to the surfaces of certain food packages, food products and especially to citrus fruits.
It is an object of this invention to provide an ink for use in the ink jet printing of indicia on food surfaces which combines properties necessary for satisfactory operation of the ink in the printing apparatus with the properties necessary for obtaining and preserving a satisfactory printed image on the particular food substrate.
It is a further object of this invention to provide an ink suitable in all respects for applying indicia to the surfaces of food products and particularly citrus fruits.
Further objects will become apparent from the following specification and claims.